Australia coach Robbie Deans has defended playmaker Quade Cooper following his erratic performance during the Wallabies' World Cup semi-final victory over South Africa on Sunday.

The Queensland Reds fly-half struggled during the Wallabies 11-9 victory, with his kicking game particularly poor. But Deans insisted that Cooper's performance was not as bad as some critics suggested and backed the No.10 to star against the All Blacks in the semi-final at Eden Park next weekend.

"He's a pretty resilient character, Quade, as you've already seen," Deans said. "He's delighted, as we all are, that we got through that challenge and he was a part of that.

"He did some good things within that that were the point of difference on occasions. Clearly, he wouldn't have been happy with his performance, but everyone made mistakes.

"Some of our best (performers) made mistakes, but collectively they worked their way through it."

The 23-year-old was already under huge scrutiny following a series of comments that have enraged the New Zealand rugby fans. Large sections of fans booed the fly-half during Australia's win over the Springboks and Deans admits the extra pressure may have contributed to a lacklustre performance.

"That can create some challenges when things don't go quite so well," he said. "(When) their piece of it isn't what they hoped it would be, it can bring mental baggage. But I think Quade has come a long way in terms of his understanding around that it's a team game.

"It's about helping the team to get up and he did that, so he'll be fine. We're confident he'll bounce back."

Meanwhile, fullback Kurtley Beale, who is struggling with a hamstring injury, and prop Sekope Kepu, who has an ankle problem, are doubts for Sunday's semi-final